104 THE ARTICULATIONS 



and others are (le(>i)or, and extend only from one vertebra to tlie next Init one 

 l)elow. 



The dentated ox In-oader jiortions (fig. 202) are formed by ol)hque fibres wliieh, 

 sprini;in<r from the bo(Hes near the intervertebral foramina, take a curved course 

 downwards and liackwards over an intervertebral substance, and reach the narrow 

 portion of the li,<jcanicnt on the centre of the vertebra next below; they then diverge 

 to i)ass over another intervertebral disc to end on the body of the vertebra beyond, 

 near the intervertebral notch. They thus pass over two discs and three vertebra\ 

 Deeper still are other fibres thickening these expansions of the common ligament. 

 and extending from one bone to the next. 



The last well-marked expansion is situated between the first two segments of 

 tlie sacrum : below this, the ligament becomes a delicate central band with rudi- 

 mentarv expansions, being more pronounced again over the sacro-coccygeal joint, 

 and losing itself in the ligamentous tissue at the back of the coccyx. The dura 

 mater is tightly attached to it at the occipital bone and margin of the foramen 

 magnum, but is separated from it in the rest of its extent Ijy loose cellular tissue. 

 The filum terminale becomes blended with it at the lower part of the sacrum and 

 l)ack of the coccyx. 



The lateral or short vertebral ligaments (fig. 200) consist of numerous short 

 fibres situated between the anterior and posterior common ligaments, and passing 

 from one. vertebra over the intervertebral disc, to which it is firmly adherent, to 

 the next vertebra below. The more superficial fibres are more or less vertical, but 

 the deeper decussate and have a crucial arrangement. They are connected with the 

 deej^ surface of the anterior common ligament, and so tie it to the edges of the 

 bodies of the vertebra and to the intervertebral discs. They blend liehind witli 

 the ex])ansions of the posterior common ligament, and so complete the casing round 

 each ampliiarthrodial joint. In the thoracic region, they overlie the stellate liga- 

 ment, and in the lumbar they radiate towards the transverse processes. In the 

 cervical reoion they are less w'ell marked. 



(6) The Lig.\ments connecting the Articular Processes 

 Class, — D'larthrosis. Subdivision. — A rthrodia. 



The capsular ligaments (fig. 194) which unite these processes .are composed 

 ]iartly of yellow elastic tissue, and partly of white fibrous tissue. In the cervical 

 region only the inner side of the capsule is formed by the ligamenta suliflava, 

 which in the thoracic and lumbar regions, however, extend anteriorly to the 

 margins of the intervertebral foramina. The part formed of white fibrous tissue 

 consists of short, well-marked fibres, which in the cervical region pass o]:)liquely 

 downwards and forwards over the joint, between the articidar i»rocesses ancl the 

 posterior roots of the transverse processes of two contiguous vertebrge. In the 

 thoracic region the fibres are shorter, and vertical in direction, and are attached to 

 the l>ases of the transverse processes; in the lumbar, they are obliquely transverse. 

 The capsular ligaments in the cervical region are the most lax, those in the lumbar 

 region are rather tighter, and those in the thoracic region are the tightest. 



There is one synovial membrane to each capsule. 



(c) The Ligaments uniting the Lamina's 



The ligamenta subflava (fig. 203) are shallow plates of closelv-woven yellow 

 elastic tissue. interi)osed Ijetween the laminae of two adjacent vertei^rtv. The first 

 connects the axis with the third cervical, nnd the last the fifth lumbar Avith the 

 sacrum. Each ligament extends from the inner and ])osterior edge of the inter- 

 vertebral foramen on one side to a corresponding point on the other; above, it is 

 attaehed close to the inner margin of the inferior articular })rocess and to a well- 

 marked ridge on the inner surface of the lamina? as far as the root of the si)ine; 

 below, it is fixed close to the inner margin of the superior articular process and to 

 the dorsal aspect of tlie upper edir,- ,,f the laminae. Thus each, besides filling ui> 



